We have stayed for just 2 nights at Alicourts, several years ago as a stopover site and the kids loved the pools and lake. You have to drive anywhere from the site but it's a good area to cycle in. (Our kids preferred beach sites for longer stays).Haven't been to the others, so can't compare

We stayed in chateau des marais but it was about 5 years ago so not sure its that relevant. Site was lovely - huge bit not to crowded. Pool was cold and that was an issue with 2 young children. They lived the slides and lazy river though.You need to drive to get pretty much anywhere and other areas of the Loire seemed more picturesque. However it was amazing being so close to chambord. We went a few times on bikes and could have spent longer there.